title: Oxidative stress in hemodialyzed patients and the long-term effects of dialyzer reuse practice.
abstract: OBJECTIVE
  To investigate the existence of an altered oxidant/ antioxidant balance in patients on regular hemodialysis treatment (RHT) and whether there is any effect of dialyzer reuse on oxidative damage and antioxidative mechanism.
  
  
  METHODS
  Malondialdehyde (MDA) levels and glutathione peroxidase (GPx) activities in both plasma and erythrocytes, plasma selenium (Se) levels, and erythrocyte superoxide dismutase (SOD) activities of RHT patients were determined at the beginning and end of 4-month reuse period.
  
  
  RESULTS
  When compared to healthy controls, both plasma and erythrocyte MDA levels were found to be significantly higher in RHT patients before the dialyzer reuse practice; whereas both plasma and erythrocyte GPx activities, erythrocyte SOD activity, and also plasma Se levels were lower in the same patient group than those of controls. When statistical comparison was made on RHT patients between before and after the reuse period, the decreases in MDA levels but increases in the enzyme activities and also an increase in plasma Se levels were observed after the reuse period. However, erythrocyte SOD activities and plasma Se levels measured after the reuse period were not found to be statistically different from the control values; MDA levels still remained elevated above the control values, and GPx activities were not attained to those of controls, after the reuse practice. In addition, positive correlations were found between activities of erythrocyte SOD and GPx enzymes, between GPx and Se levels and negative correlations between the activities of both enzymes and MDA levels in erythrocytes of patients on RHT.
  
  
  CONCLUSIONS
  These findings may indicate that dialyzer reuse may provide, at least partly, an improvement on oxidative stress in patients on RHT.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Erciyes University, Kayseri, Turkey. Unsal@vm.cc.erciyes.edu.tr
authors.forename: K
authors.initials: K
authors.lastname: Köse
authors.forename: P
authors.initials: P
authors.lastname: Doğan
authors.forename: Z
authors.initials: Z
authors.lastname: Gündüz
authors.forename: R
authors.initials: R
authors.lastname: Düşünsel
authors.forename: C
authors.initials: C
authors.lastname: Utaş
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D017743:Equipment Reuse; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood; D006801:Humans; D015227:Lipid Peroxidation / Q000502:physiology*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D006435:Renal Dialysis; D013997:Time Factors
chemical_list: D008315:Malondialdehyde; D005979:Glutathione Peroxidase